Toilet Flange bolts keep spinning...

Hey guys. I've got an old house with old plumbing. I'm getting ready to put a new subfloor on but I'm not raising the toilet flange because I believe it to be either cast iron or ceramic. Probably cast iron. Anyway, I've taken my toilet off in the recent past and when I put it back on, the toilet bolts just spin. I'm not sure if the flange is broken or what, but I can't tighten the bolts down extremely tight because all they do is spin once they get any tension on them. So I'm wondering if any of you have a good tip or trick to try to get them to stay in place while I tighten the toilet back down. Anything would be very helpful. Thanks a lot.

Jason

I assume you are using true flange bolts, the kind that have a flat, oblong head. You can use a flat washer and a nut to hold your flange bolts in place an keep them from spinning. There is plenty of room for the nuts under the toilet.

Awesome. Thanks for the advice, I appreciate it.